New DNA Test to Help in Global Effort to Control TB

Friday, 29 June 2012

A new diagnostic DNA test has been developed by a team at the National University of Ireland Galway to help in the global effort to control tuberculosis (TB). The rapid laboratory test allows for the identification of the exact bacteria causing a patient’s TB which will give valuable information for their treatment.

According to World Health Organisation data, tuberculosis (TB) is second only to HIV/AIDS as the greatest killer worldwide due to a single infectious agent. In 2010, 8.8 million people fell ill with TB and 1.4 million died from TB, with over 95% of cases and deaths in developing countries.

In humans, TB is caused by a group of eight bacteria collectively known as the Mycobacterium tuberculosis complex (MTC). National University of Ireland Galway’s Molecular Diagnostics Research Group has developed and validated a new assay or laboratory test called SeekTB to identify all members of the MTC.

Dr Thomas Barry at the University, along with his colleagues Dr Justin O’Grady and Dr Kate Reddington, realised there was a need to rapidly and accurately detect and identify each member of the MTC for better treatment of TB. “The optimal patient treatment can be different, depending which of the eight bacteria are causing the TB, as some of these bacteria are naturally resistant to a commonly used anti-TB drugs”, explains Dr Barry.

The new test, called SeekTB, could also prove useful to centralised clinical reference labs for the purposes of tracking and conducting epidemiological studies on the various mycobacterium species comprising the complex. “Identifying the specific member of the MTC is currently not routinely performed in testing laboratories and therefore it is unknown what the true impact each member of the MTC has on the global TB epidemic,” says Dr Barry, who lectures in Microbiology at National University of Ireland Galway.

The advance in what is a global battle against TB, is the result of international co-operation. The novel technology was initially validated by testing a large number of previously isolated MTC bacteria provided by Professor Dick van Soolingen, Bilthoven in the Netherlands and Dr Stefan Niemann, Borstel in Germany.

Subsequently, through collaborations with Professor Alimuddin Zumla and Dr Matthew Bates at University College London, SeekTB was used to successfully analyse patient samples from Lusaka in Zambia to demonstrate the technology’s suitability. The results of this analysis demonstrated the rapidity, the test only takes 1.5-3 hours to perform, validity and robustness of SeekTB.

In its current format, SeekTB is likely to be predominantly used in central testing laboratories, in Africa for example, on culture positive TB patient samples to guide appropriate treatment and control measures.

“Ideally, in the future, SeekTB could be used directly on patient samples with the test configured onto a handheld machine for use at point-of-care in resource poor settings. This could be a huge benefit to medical care provision in remote areas, however, it will likely take years of research and development to achieve such a goal,” concluded Dr Barry who acknowledged National University of Ireland Galway and the Thomas Crawford Hayes award for funding this work.

The research has recently been published in the Journal of Clinical Microbiology and PLoS ONE.